Tropical kudzu in Puerto Rico

Historic, Archive Document

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scientific knowledge, policies, or practices.

TROPICAL KUDZU

in Puerto Rico

CIRCULAR NO. 27
Federal Experiment Station in Puerto Rico
UNITED STATES DEPARTMENT OF AGRICULTURE
Office of Experiment Stations

FEDERAL EXPERIMENT STATION IN PUERTO RICO

MAYAGUEZ, PUERTO RICO

Administered by the Office of Experiment Stations
Agricultural Research Administration
United States Department of Agriculture

R. W. Trullinger, Chief, Office of Experiment Stations

STATION STAFF
Kenneth A. Bartlett, Director.

Norman F. Childers, Assistant Director, Plant Physiologist.

Merriam A. Jones, Chemist.

Arnaud J. Loustalot, Chemist.

Haroi*> K. Plank, Entomologist.

Edward P. Hume, Horticulturist.

Harold F. Winters, Horticulturist.

David G. White, Plant Physiologist.

Caleb Pagan Carlo, Scientific Aide.

Carmelo Alemar, Administrative Assist ant.

Hilda J. Carrero, Clerk-Stenographer.

Juan a F. Cedo, Clerk-Stenographer.

William Vargas, Property Clerk.

Jose B. Huyke, Collaborating Agricultural Engineer.1

Hector R. Cibes Viade, Collaborating Agronomist.1

Ruben H. Freyre, Collaborating Agronomist.1

Pedro Seguinot Robles, Collaborating Agronomist.1

Aida Gauthier de Villafane, Collaborating Agronomist.1

Noemi G. Arrillaga, Collaborating Chemist.1

Gilda C. Vicente, Collaborating Chemist.1

Felix Antonio Rosado, Cooperating Laboratory Helper.1

Julia Lopez, Cooperating Clerk-Stenographer.1

Susana Rodriguez, Cooperating Clerk-Stenographer.1

Iris C. Vera, Cooperating Clerk-Stenographer.1

Astor Gonzalez, Sus, Cooperating Librarian.1

Victoria Maldonado, Cooperating Library Assistant.1

Cover Illustration. — Tropical kudzu is a vigorous, deep-rooted leguminous vine,
which is relatively resistant to drought and when well established can be de-
pended upon to supply forage for livestock during the dry season. Other
valuable features of tropical kudzu are described in this circular.

1 In cooperation with the Government of Puerto Rico.

ii

FEDERAL EXPERIMENT STATION IN PUERTO RICO

of the

UNITED STATES DEPARTMENT OF AGRICULTURE

MAYAGUEZ, PUERTO RICO

CIRCULAR NO. 27

Washington, D. C. March 194'

TROPICAL KUDZU IN PUERTO RICO

By Emery A. Telford, associate conservationist, Soil Conservation
Service, and Norman F. Childers, senior plant physiologist, Fed-
eral Experiment Station in Puerto Rico.1

CONTENTS

Page I

Introduction.

1 Time of seeding.

Why a legume? 7 | Rate of seeding

History and botany of Pueraria

phaseoloides 7

Climatic requirements 10

Soil requirements 10

Planting methods and preparation

of seedbed 13

Seed treatment and germination 19

Page

20

21

Method of seeding 21

Fertilizers 21

Pasturing 23

Harvest of seed 24

Insects and diseases 27

Literature cited 28

Additional references 29

INTRODUCTION

There has been a long-time need in Puerto Rico for a vigorous
legume similar to the kudzu (Pueraria thunbergiana (Sieb. and
Zucc.) Benth.) which is widely planted in the southern United States
for soil erosion control and as a pasture and hay crop. The island has
thousands of acres of inland unproductive hillsides, erosion gullies,
and relatively poor pasture areas which could be profitably planted
to such a crop. Unfortunately, P. thunbergiana has not grown satis-
factorily under tropical conditions in Puerto Rico. The plants make
fair growth for a few months, then become more or less dormant ; also,
the hairless leaves are highly susceptible to attack by the velvetbean
catepillar (Anticarsia geinmatiUs (Hbn.) ). A similar unsatisfactory
response of P. thunbergiana is reported in Hawaii, where it has been
tested from sea level to 4,000 feet elevation (13) . 2

In 1940 the Soil Conservation Service of the United States Depart-
ment of Agriculture in Puerto Rico introduced seed of another species
of Pueraria known as P. phaseoloides (Roxb.) Benth. (P. javanica
Benth.)3 which has been locally named "tropical kudzu." Under

1 The authors sincerely appreciate the constructive contributions made by the
following : Kenneth A. Bartlett, director of the Federal Experiment Station ;
R. Y. Bailey, senior conservationist, Spartanburg, S. C. ; R. N. Jobe, associate con-
servationist, Mayaguez, P. R. ; and U. S. Allison, director, Soil Conservation Serv-
ice, San Juan, P. R.

2 Italic numbers in parentheses refer to Literature Cited, p. 28.

3 Seed brought to Puerto Rico by Dr. W. F. Stewart, Boyce Thompson Institute,
Yonkers, N. Y., from Rubber Research Institute of Malaya, Kuala Lumpur,
Selangor, Federated Malav States.

1

2

CIRCULAR NO. 2 7, FEDERAL EXPERIMENT STATION

Puerto Eican conditions tropical kudzu exhibits most of the outstand-
ing* qualities of its close relative in the southern United States and,
in some respects, it is superior in that it seeds heavily, is readily estab-
lished from seed, and grows 12 months of the year. With regular
rains it thoroughly covers the ground in the comparatively short time
of 6 months. On bare land, its dense foliage assists in reducing soil
erosion caused by beating raindrops (fig. 1) which is common on

Figure 1. — The heavy beating of tropical raindrops on bare soil is an important
erosion factor in Puerto Rico. Note protection given by dead leaves perched
on columns of soil. Note, also, invading runners of tropical kudzu, which will
anchor the soil within another 2 months.

TROPICAL KTJDZU IX PUERTO RICO

3

barren land in regions of heavy and frequent tropical downpours.
The dense cover also catches and holds considerable rainfall which
is absorbed by the soil. Tropical kndzn has several other qualities:
It is relatively resistant to drought, grows well in full sun and be-
neath moderate shade (fig. 2, -A)y has no serious insects or diseases,
and makes good pasture or hay for dairy cows. (See cover photo.)
The legume tends to spread from an original planting when seeding
is permitted, but there is no evidence that it will become a pest.

The trailing runners of tropical kudzu may extend 20 feet or more
up and down banks, under trees, and over grasses, bushes, and weeds
until most of the undergrowth is smothered. It competes successfully
with such forbs and grasses as nut grass (Gyperus rotundus L.),
carpet grass (Axonopus compressus (Swartz) Beauv.), guinea grass
(Panicum maximum Jacq.), molasses grass (Melinis minutifora
Beauv.), and Para grass, or malojillo (P. purpurascens Raddi). It
covers the ground more thoroughly and quickly under pasture trees
than some grasses, such as molasses grass (see fig. 3). When planted
among trees, it has a tendency to climb upon the limbs and trunks
(fig. 2, A), but the runners can be removed at 1- to 3-month intervals
and the labor involved is considerably less than that required to cut
with a machete the natural growth of the entire area. Mclndoe 4
recommends removing a 3- to 5-foot diameter ring of Pueraria growth
from around the base of each tree. It is especially important that the
runners of tropical kudzu be removed from young trees at regular
intervals to prevent breaking of limbs or felling the entire tree. With
older trees frequent cutting is not so important.

One of its primary uses in the Far East is for ground cover to pre-
vent soil erosion and loss of fertility after clearing jungle for rubber
and cinchona plantations. The Firestone Plantations Co.. in Liberia,
West Africa, has used Pueraria phaseoloides since 1929, and recently
reported over 30,000 acres planted among young and maturing rubber
trees. Heilman 5 of that company states that, ". . . among numerous
cover crops tried in Liberia, this particular one dries out the least
during several months of drought and, consequently, does not present
a serious fire hazard. Some disastrous fire experience has been en-
countered with Calopogoniunv mucunoides Desv.*5

Mclndoe,6 of the Firestone Co., states that the thick mat of Pueraria
apparently will persist indefinitely in open areas. In the rubber plan-
tations when the trees reach 5 years of age, however, the green mat
begins to thin out, and in dense unthinned rubber plantings the
Pueraria may disappear entirely. This is especially true on some soils.
On the most fertile soils, however, the Pueraria may persist very well
even under the shade of old rubbertrees both in Liberia and Sumatra.
He has not been successful in establishing the crop under already exist-
ing shade. Soils in Liberia are of a red gravelly lateritic type,
definitely acid in reaction. The plant thrives equally well on the
fertile lowland and rocky, less fertile upland soils.

4 McIndoe, K. G. In correspondence from Firestone Plantations Co., Monrovia,
Liberia, West Africa. 1945.

6 Heilman, H. W. In correspondence from Firestone Plantations Co., Akron,
Ohio. 1945.

6 See footnote 4, above.

4

CIRCULAR NO. 2 7, FEDERAL EXPERIMENT STATION

Figure 2. — A, A heavy crop of tropical kudzu growing under the moderate shade
of a mango tree. This crop makes a good ground cover between economic tree
plantations, but the runners must be removed from the young trees at regular
intervals to prevent them from breaking limbs. B, Tropical kudzu growing on
so-called unproductive Nipe clay near Maricao, P. R.

TROPICAL KUDZU IN PUERTO RICO

5

Figuee 3. — Six months after planting tropical kudzu (A) and molasses grass (B)
the kudzu had completely covered the ground beneath a tree, whereas the
molasses grass in a neighboring plot had grown only to the perimeter of the
tree, as shown by the dash line. The long runners of tropical kudzu enable it to
thrive beneath trees in spite of the latter's competition.

6

CIRCULAR NO. 2 7, FEDERAL EXPERIMENT STATION

Ashplant (1) and Mclndoe report better growth of rubbertrees
with a cover crop of Pueraria. Ashplant reports a definite reduction in
death of rubbertrees from Fomes root rot when a cover of Pueraria is
employed in Sumatra.

A recent report by Schofield (IS) from northern Australia shows
the superior value of Pueraria phaseoloides as compared with fallow
soil and three other popular tropical legumes, namely, Oentrosema
pubescens Benth. (centro), C alopogonium muciinoides Desv. (calopo),
and Stylosanthes guianensis Sw. (stylo). The climatic conditions
under which Schofield's experiments were performed appear to be
similar to those in Puerto Rico. He summarizes his work and gen-
eral experience with P. phaseoloides (puero) under the conditions of
northern Australia as follows :

Under conditions in the ''wet tropics/' puero — which is closely related to
Kudzu and is in fact its tropical counterpart — has proved to be a legume of out-
standing value. It is used extensively in Malaya and Sumatra as a plantation
cover crop to assist in maintaining soil fertility and in the prevention or control
of erosion, and its ability to withstand light shade has extended its usefulness
considerably. The results obtained in this experiement (fig. 4)) demonstrate
that large quantities of nitrate nitrogen are produced rapidly during its de-

300

Figure 4. — Nitrate in the 6- to 12-inch layer of soil 6 days after above legumes
were plowed under in northern Australia. Legumes were established from
seed and grown for 18 months; all results were highly significant. Note
superior value of puero, Pueraria phaseoloides. (After Schofield (15, p. 187).)

composition after ploughing under a crop grown for 18 months ; and this is quite
apart from its value as a source of humus, which w^ould not be inconsiderable.

Puero is easy to establish from seed or cuttings, and it is so aggressive that it
has been used successfully as a weed-smother crop. Puero roots freely at the
nodes under suitable conditions and forms a carpet 2 feet deep, completely
covering the soil, shading it from the sun, preventing the direct impact of rain,
and ensuring adequate protection against soil erosion. It is a rather shy seed-
bearer, and thus little trouble from self-regeneration occurs when an area of
the crop is ploughed and the land placed under cultivation. The beneficial
effect on soil structure of the organic residues from the various legumes,
especially puero, is a further factor of the utmost importance. . . .

Puero is palatable and may be of special value as a pioneer legume in the
rehabilitation of rain-forest areas which have been opened and planted to grass,
but where the topography precludes ploughing as a means of overcoming weed-
infestation prior to replanting. It may in addition be used with advantage on
areas where ploughing can be undertaken, but where the soil is low in nitrogen

TROPICAL KUDZU IX PUERTO RICO

7

and humus and weeds have taken possession ; that is on worked-out, washed-
out, "dead" soils. Experimental work has indicated that the planting of single-
or double-furrow strips, 10 to 15 feet apart on the contour, may be sufficient to
allow puero to become established and smother out the weeds.

WHY A LEGUME?

The use of legumes in rotation has long been recognized as the
soundest and most economical method of raising and maintaining the
productivity of the soil (8) . This is chiefly because legumes have
the ability to accummulate nitrogen from the air through nodule-
forming bacteria in the roots. Some leguminous plants are able to
grow on eroded areas too poor to support other plant growth and,
ultimately, they raise the nitrogen and organic matter content of the
soil to a level at which pasture grasses wTill grow.

Legumes often will stimulate the growth of grasses in a mixed
pasture (6). This has been noted at Eio Piedras, P. E., where better
growth of Para grass was obtained when grown in combination with
tropical kudzu. Some legumes, including tropical kudzu, make
growth during seasons when grasses are less vigorous, as, for example,
during the winter season in Puerto Eico, and, therefore, make good
mixtures with grasses. For feeding, legumes are of exceptional value
because they are rich in calcium, protein, and certain vitamins (15).
They make up for constituents frequently deficient in grasses.

Generally speaking, legumes are more difficult than grasses to
establish and maintain in a pasture. This is mainly because the grow-
ing buds of legumes are eaten off by the grazing livestock, whereas
buds of grasses are enclosed and are level with or slightly beneath the
soil surface. It should be emphasized, however, that the inclusion
of legumes in a pasture mixture is a basic feature of sound grazing
husbandry in the Temperate Zone, and it has been found that livestock
forage consisting of a legume-grass mixture is more economical and
profitable than a forage of grasses alone. In Puerto Eico there is a
definite need among dairymen for a high-protein legume for forage.
Protein concentrates are shipped into the island in large quantities,
and they constitute the most expensive part of the ration.

HISTORY AND BOTANY OF PUERARIA PHASEOLOIDES

Pueraria phaseoloides appears to be relatively little known in the
Western Hemisphere, but it has been grown for many years in the Far
East — in Malaya, Sumatra, Ceylon. Java, South China, and neighbor-
ing countries. Its origin is not definitely known, although Bunting
and Milsum (7, pp. 270-271) and state that it is indigenous to Malaya.
The literature contains at least one reference and description dating
back to 1867 ( J, p. 125) . In the Far East there are many local common
names for this plant, but apparently the research workers have been
content with calling it "Pw&raria" Pueraria javanica, or P. phaseo-
loides, of which the latter is preferred.

Tropical kudzu is a vigorous, leguminous vine which has soybean-
like leaves (fig. 5). The numerous above-ground stolons intertwine
and cling tenaciously to the soil by taking root at the nodes and inter-
nodes (fig. 6, 2?), which make it an ideal soil erosion control crop. It

717596 — 47 2

8

CIRCULAR NO. 2 7, FEDERAL EXPERIMENT STATION

has a deep and widely branching root system as shown in figure 6, A.

Herbarium specimens of tropical kudzu were sent to the Division
of Plant Exploration and Introduction, United States Department of
Agriculture, from which the following botanical description8 was
derived :

Pueraria phaseoloides (Eoxb.) Benth. (Fabaceae)

A twining vine, clothed with dense spreading brown hairs ; leaves trifoliolate ;
stipules small, lanceolate, basifixed ; leaflets membranous, green, and thinly
clothed with appressed hairs above, gray and more or less densely matted beneath,
the terminal leaflet very variable in size and shape, usually broadly ovate to
rhomboidal, entire or rarely somewhat 3-lobed, 6-15 centimeters long; flowers
in long-peduncled racemes; pedicels 3-8 millimeters long; bracteoles lanceolate,
2-3 millimeters long, strongly nerved, strigose and hirsute; calyx 5 millimeters

Figure 5— A, Tropical kudzu {Pueraria phaseoloides (Roxb.) (Benth.) is a
vigorous perennial stoloniferous legume which can be used for pasture or cover
crop or in controlling soil erosion. It fruits heavily from December to February.
The flowers are lavender with white fringes, and the leaves resemble soybean
leaves. B, The laminated pods are black with dark-brown to yellowish seeds.

long, strigose and bristly hirsute, the teeth 1.5-2 millimeters long, broadly oblong
and abruptly acute except the lowermost which is lanceolate with setaceous tip;
corolla deep to light lavender, often with whitish fringes, 15 millimeters long;
blade of standard roundish, distinctly spurred ; pod 6-10 centimeters long, 4 milli-
meters wide, black when ripe, trigose, rather turgid, 15-20 seeded.

8 The authors appreciate the assistance of F. J. Hermann, associate botanist,
Division of Plant Exploration and Introduction, U. S. Department of Agriculture,
for aid in identification and preparation of a botanical description of Pueraria
phaseoloides.

TROPICAL KUDZU IN PUERTO RICO

9

Until 1945, 17 introductions of Pueraria phaseoloides had been made
into the United States, and from table 1 it is apparent that these in-
troductions came from widely separated tropical countries, including
three in Latin America.

1 MM > — •

2 MM. — - h\

2 mm < - «

« j3* »

Figure 6. — A, A ditch was dug 4 feet deep and 13 feet wide to study root distri-
bution of 2-year tropical kudzu. Although most of the roots were in the upper
foot of this heavy Catalina clay soil, it is apparent that several large roots had
penetrated to a depth of 4 feet or more. B, On the soil surface near the ditch
shown in A, vegetation was pulled back to show the thick mat of tropical kudzu
rooted to the soil. Note root nodules above the pencil point.

10

CIRCULAR XO. 2 7, FEDERAL EXPERIMENT STATION

Table 1. — Introductions of Pueraria phaseoloides into the United
States by the Division of Plant Exploration and Introduction,
United States Department of Agriculture

Plant introduction Xo.

27491
30964
47850.
66256.

102775.
130946
132998.
133961.
133962.

136644.
137643.
143802.
145021.

148446.
148883.
148993.
150702.

Source

Darjeeling, India

Lamao, P. I

Darjeeling, India

Kandy, Ceylon, India.

Darjeeling, India

Costa Rica

Sumatra, East Indies,

Island of Reunion

Mindanao, P. I

Netherlands East Indies.

Java

Brazil

Colombia

Belgian Congo

Liberia

Nigeria

Received

1910
1911
1919
1926

1933
1938
1939

1939

1940
1940
1942
1942

1944
1944
1944
1945

CLIMATIC REQUIREMENTS

Pueraria phaseoloides grows and seeds best in Puerto Rico where
minimum rainfall is not less than about 50 inches a year. At May-
aguez, it grows luxuriantly under average annual rainfall conditions
of 81.5 inches, with a winter dry season of about 3 to 4 months'
duration beginning in November. Tropical kuclzu has been grown
successfully from about sea level at Mayaguez to 3,200 feet in the
Toro Negro Mountains, where winter night temperatures on some occa-
sions fall to 50° F. The growth is somewhat slower and more stocky
at Toro Negro than at Mayaguez especially during the winter season,
as a result of the approximately 5° F. lower mean temperature. In
Liberia 2 years after planting among rubber trees, it makes dense
growth about 2 feet deep. Annual rainfall in Liberia averages about
130 inches, with a dry season extending from November to February.
Under climatic conditions in British Guiana favorable results have
been reported recently by Williams 9 in preliminary trials.

Results with tropical kudzu in a temperate climate have been unsat-
isfactory. According to Scott,10 P. phaseoloides has been grown at
Thorsby, Ala., CofTeeville, Miss., and Chapel Hill, N. C., where the
growth was vigorous, but the plants were killed by frost. It is
probable that tropical kudzu would grow successfully in frost-free
areas of the southern United States.

SOIL REQUIREMENTS

Tropical kudzu does not appear to be exacting in soil require-
ments. At the station, it grows satisfactorily on heavy clay subsoil

9 Williams. H. B. In correspondence from the Department of Agriculture of
British Guiana. 1945.

10 Scott, L. B. In correspondence from the United States Soil Conservation
Service, Spartanburg, S. C. Oct. 1945.

TROPICAL KUDZU IN PUERTO RICO

11

with an approximate acidity of pH 5.0 (fig. 7). In a stiff Catalina
clay soil (pH 4.5), the roots of a 2-year plant were found to pene-
trate vertically with little difficulty to a depth greater than 4% feet,
as shown in figure 8. No doubt this accounts for its ability to con-

FiGURE 7. — The upper 2 feet of surface soil on this 40-percent slope was removed
6 years previously and maintained under clean cultivation until tropical kudzu
was planted in March 1945. By planting kudzu the soil-erosion loss from
this plot was reduced from an average of 2,300 pounds per acre per inch of
rainfall to about 50 pounds in September 1945. Above photo was taken
in November. Amount and intensity of rainfall was about the same for
these two comparison periods. In June 1946 a 1.9-inch rain fell in 1 hour
on the run-off plots. The kudzu cover absorbed 91 percent of the rain water
whereas the nearby well-established sugarcane plots absorbed 16 percent
less, or 75 percent.

12

CIRCULAR NO. 2 7, FEDERAL EXPERIMENT STATION

Figure 8. — In micldry season, a planting of tropical knclzu was noted to be
withstanding drought better than neighboring pasture crops. Vertical roots
of this 2-year plant were traced to a depth of at least 4y2 feet in the heavy
clay soil.

TROPICAL KUDZU IN PUERTO RICO

13

tinue growing slowly during extended dry periods when other le-
gumes, such as trailing indigo {Indigofera endeca/phylla Jacq.), show
considerable distress.

Good crops of tropical kudzu also have been grown on sandy loams
used in road fills near Anasco and Guajataea, P. R. On Las Mesas
and near Maricao (fig. 2, B) , the crop is making good growth on Nipe
clay of pH 4.6-5.1, which is considered by Roberts {1J±, p. 200) to be
low in lime and phosphorus and, in fact, the most unproductive soil
in Puerto Rico. Applications of a complete fertilizer, 10-10-5, were
used in most of the above cases to obtain a stand of tropical kudzu.

At Mayaguez, the crop has withstood excess soil moisture con-
ditions, where water stood in spotted areas on the soil surface for
a week or more after the frequent and heavy summer rains. Where
there is a heavy stand of tropical kudzu on such areas, the long
runners are usually anchored here and there on drier areas, from
which most of the nutrients are probably derived during periods of
excess soil moisture. In Liberia, Mclndoe 11 reports that the plant
thrives on low, recently drained swamps where the water table is
6 to 12 inches below the surface.

On fertile lowland soil in Puerto Rico, as in Liberia 11 the experi-
ence has been that weeds tend to give the Pueraria seedlings stiff com-
petition and more frequent weedings are usually necessary to obtain
a kudzu cover. It has been shown at Mayaguez, however, that once
tropical kudzu is established on fertile lowland, it competes success-
fully with other vegetation, and excellent yields of kudzu can be
obtained.

PLANTING METHODS AND PREPARATION OF SEEDBED

On upland rolling and hilly soil or on undulating more or less bare
land, tropical kudzu should be planted in strips or hills in order to
prevent soil erosion while the plants are becoming established. Strips
can be plowed on the contour (fig. 9) and spaced from 15 to 25 feet
apart, center to center, depending upon the seed and labor available,
steepness of the slope, and the rapidity with which a complete ground
cover is desired. The uncultivated native strips of grass between the
cultivated areas will assist in controlling erosion while the kudzu is
taking over.

Kudzu planted in hills 6 feet apart in plowed strips spaced 20 feet
apart requires, with proper management, approximately a year to
cover the ground completely. With this spacing, two or more weed-
ings will be necessary in the seedbeds to control the tall-growing weeds
and bushes. As the kudzu runners reach the outer borders of the
cultivated strips, two or three additional furrows are plowed toward
the vines at about monthly intervals until eventually the entire hill-
side has been plowed and become covered with kudzu. The plowing
reduces weed competition and helps the runners take root.

The hill system of ground preparation and planting (no plowing)
can be employed, but somewhat more hand labor is required. It is
a convenient system where small areas of ground are to be planted
and it is not worth while to use a plow. Patches of ground 3 feet in

See footnote 4, p. 3.

14

CIRCULAR NO. 21, FEDERAL EXPERIMENT STATION

diameter are spaded and prepared. The hills may be spaced, depend-
ing upon conditions, from 3 to 18 feet apart on the square. In young
rubbertree plantations,12 2-foot diameter hills are placed in the center
of the squares of trees which makes a spacing of about 18 feet, depend-
ing upon the planting distance of the young trees. Aside from a
few initial weedings, no fertilization or additional cultivation atten-
tion is given. Under these conditions considerable runner growth is
obtained in 12 months and a complete heavy cover within 18 to 24
months.

Figure 9. — On hilly land, tropical kuclzu is best established by plowing strips
3 to 6 feet wide on the contour and planting the seed in hills. ( See fig. 10. ) The
strips of native vegetation prevent erosion while the kuclzu is taking over.
As the kudzu runners reach the .outer borders of the cultivated strips, two
or three additional furrows are plowed toward the vines at about monthly
intervals until eventually the entire hillside has been plowed and has become
covered with kudzu. Plowing facilitates rooting of the runners.

In Puerto Rico best seedling growth has been obtained where the
seedbed was plowed or spaded to a depth of 6 to 10 inches and har-
rowed and worked into a flne-texturecl bed, If the soil is low' in
fertility, fertilizer is worked into the upper 3 or 4 inches of soil as
described in figure 10. A good cover of tropical kudzu was obtained
at Mayaguez in 7 months on heavy excavated soil where shallow fur-
rows about 3 feet apart were made on the contour into which the seed
were dropped and left for the rain to cover with silt (fig. 11). There
was no previous spading or cultivation of the seedbed. Growth of

See footnote 4, p. 3.

TROPICAL KUDZU IN PUERTO RICO

15

Figure 10. — On the contour strips, shown in figure 9, slightly sunken areas are
prepared with a mattock at 6-foot intervals. If the soil is low in fertility,
one-eighth pound of 10-10-5 fertilizer is worked into the upper 3 to 4 inches
of soil. A pinch of seed is sown on top of the soil and firmed with the foot.

the seedlings under these conditions was slow, however, especially
where no complete fertilizer and lime were added (soil pH 5.2). It
should be emphasized that tropical kudzu seedlings by nature grow
slowly for the first 3 to 4 months (fig. 12) and they require special
weeding and cultivation during this time to speed the growth as
much as possible. Once they are well established at 5 months, how-
ever, growth is rapid. Mclndoe13 suggests mixing seed of Calopo.

13 See footnote 4, p. 3.

16

CIRCULAR NO. 2 7, FEDERAL EXPERIMENT STATION

gonium mucunoicles with the Pueraria at planting, since the former
grows more rapidly in the beginning and helps give an early covering
while the more vigorous Pueraria eventually takes over.

Tropical kudzu is an excellent crop to cover shallow or deep eroded
gullies (fig. 13, B) , stop the moving soil, and thus gradually build up
the gully floor. In the case of a large gully, 3-foot-wide strips of
ground are prepared on either side of the gully at a distance of about
3 feet from the edge. With proper initial fertilization and weeding,
the kuclzu after 6 months should make rapid growth of runners which
after 9 to 12 months may extend 20 feet or more into the gullied area.
Such treatment of gullies not only controls erosion, but may turn
formerly valueless land into productive forage areas for dairy cattle
and other livestock, provided the character of the gullies is not danger-
ous to grazing livestock.

Figure 11. — A, Soil was excavated to a depth of 25 feet to build the station
water-storage tank on the left. Tropical kudzu was planted on the subsoil
on the contour in rows only 3 feet apart in order to arrest erosion quickly.
B, This photograph shows coverage by tropical kudzu 7 months later. One
weeding was necessary 5 months after planting to destroy tall-growing plants.

Where Para grass or similar grasses are being grown on either bench
or Nichols terraces, rows of tropical kudzu can be planted along the
edge of each terrace to assist in holding the terrace and also intermingle
with the grasses and increase the protein content of the combined cut
forage.

If the slope of the land is gentle or almost level, a planting plan
can be used in which four- to six-row strips of a grass such as Para
grass or molasses grass are planted in rows about 2 feet apart, and
these strips alternated with a two-row strip of tropical kudzu planted
in rows 3 feet apart. Both Para grass and molasses grass are rela-
tively low growing, and tropical kudzu readily intermingles with them.
The kudzu will not smother the grasses if pastured or cut regularly
(fig. 14.) It also can be grown similarly with elephant grass, guinea

TROPICAL KTJDZU IN PUERTO RICO

17

grass, and Guatemala grass, but about four rows of tropical kuclzu may
be needed to successfully compete with these more vigorous grasses.

In regions of the island where field corn is grown, one row of tropical
kudzu can be sown in every fourth to sixth row of corn. At Mayaguez,
for example, the kudzu begins to take over about the time the corn is
harvested and thence grows vigorously during the summer and early
winter months, producing excellent pasture. The land can be left in
kudzu for several years or pastured and plowed the following spring

Figure 12. — Seedlings of tropical kudzu grow slowly during the first 3 months,
and it is important that they receive weeding and cultivation. The 4-month
seeding at Toro Negro, 3.200 feet altitude, is beginning to send out runners.

18

CIRCULAR NO. 2 7, FEDERAL EXPERIMENT STATION

Figuee 13. — A, On infertile heavy clay soil tropical kudzu was readily established
from seed planted in June (left), whereas trailing indigo planted with cuttings
(right) was almost a complete failure. Photo taken 6 months after planting.
B, Tropical kudzu planted in hills 3 feet from the edge near the head of a gully
filled the gully in 6 months and stopped further erosion.

TROPICAL KUDZU IN PUERTO RICO

19

for another planting of corn. Ordinarily, there are enough stem and
root cuttings of tropical kudzu from the first planting to gradually
take over after the second corn crop has matured.

SEED TREATMENT AND GERMINATION

In relation to other tropical seed, Pueraria phaseoloides is excep-
tional in Puerto Rico in that its viability usually remains above 90-per-
cent germination for at ]east 1 year under room temperature and
humidity conditions. At Mayaguez, one batch of seed showed a germi-
nation of 68 percent after 3 years' storage in glass-stoppered jars under
ordinary room conditions. Trials have indicated that seed over 6
months of age germinate more readily than seed less than 6 months of

Figure 14. — Tropical kudzu and Para grass compete with each other favorably to
produce a combined forage which is higher in protein than grasses alone.
Tropical kudzu can be seen climbing elephant grass in the background.

age. There seems to be no serious insect pests or diseases of the seed
in storage.

The seed coat is hard, and some kind of scarification is needed, es-
pecially on the older seed. Acid treatment is recommended for better
germination and quicker emergence. The seed is cleaned and placed
in a solution of equal parts of sulfuric acid and water 14 and stirred
frequently during a period of about 30 minutes, then ivashed thor-
oughly with water and dried. It is best to plant immediately after
treatment. Fair to good germination also has been obtained at this
station by soaking the seed in water for 24 hours, inoculating, and

"The solution is prepared by mixing concentrated commercial sulfuric acid
(H2SO4) with an equal volume of water. To mix, carefully pour the acid into
the water and allow to cool before adding the seed.

20

CIRCULAR NO. 2 7, FEDERAL EXPERIMENT STATION

planting immediately in moist soil. Most of the acicl-treatecl or water-
soaked seed will germinate within about 10 clays, whereas untreated
seed germinates over a period of 3 to 4 weeks and the germination per-
centage is usually considerably lower.

Another recommended method of scarification 15 is to rub the seed
between two sheets of sandpaper. This requires more labor but less
supervision. The same principle is employed by motor-driven
mechanical seed scarifiers on the market, which are much quicker and
more economical if large batches of seed are involved.

Sulfuric acid is poisonous and highly corrosive to skin and
clothing. Great care should be taken in using the acid or the
solution. Vessels should be thoroughly cleaned after using. The
acid should not be stored on the premises.

With legumes it is generally recommended that the seed be innocu-
lated with nodule-forming bacteria (see fig. 6, B) before planting.
This is especially true where no legumes have recently grown on the
soil. In Puerto Rico, Kinman (10) states that most of the soils con-
tain nodule-forming bacteria because of the prevalence of many native
legumes. However, if the land to be planted has been in a grass crop
for several years with no legumes, it would be a wise precaution to treat
the seed according to the manufacturers' recommendations on the con-
tainer.16 In fact, experience continues to show at this station that it
is advisable to inoculate all seed immediately before planting.

Another system of inoculating seed is to haul surface soil from a
field where tropical kudzu has recently grown. The soil is pulver-
ized, and a few hundred pounds dusted on each acre of the field to be
planted to kudzu. Or, a few pounds of the soil may be placed in
a bucket of water and stirred. After the soil has settled to the bottom
the water is poured into another bucket containing the seed. Nodule-
forming bacteria in the water suspension adhere to the seed when it is
removed.

TIME OF SEEDING

The preferred time for planting seed or cuttings of tropical kudzu
in Puerto Rico is at the beginning of the rainy season, which is usually
from April to May, although not always, as, for example, near the
village of Lares, where the best time for planting falls in September
or October. Rains assist the young plants in becoming established
and making considerable growth before the dry season. Seed planted
in June at Mayaguez has produced sufficient vegetative growth for
grazing and for heavy flowering and seeding the following December
to March.

Good stands of tropical kudzu have been obtained in 9 months near
Guajataca (annual rainfall 50 inches) by planting the seed as late as
September and October. However, the ensuing dry months limited
the growth and it required 3 to 5 months' additional time to obtain a

15 See footnote 4, p. 3.

16 Special inoculant lias been prepared for tropical kudzu by The Nitragin Co.
Milwaukee, Wis. Inoculate the seed after scarification. Keep the bacteria away
from strong light as much as possible.

TROPICAL KUDZU IN PUERTO RICO

21

good ground cover. If irrigation is available during the winter sea-
son, a good stand can be obtained in 6 to 8 months by watering to a
depth of 6 inches at 1- to 2-week intervals during extended dry periods.

RATE OF SEEDING

The amount of seed required per acre will depend upon the quantity
of seed and labor available and the rapidity with which a stand is
desired. If the hills are spaced 3 feet apart, it requires about 5 pounds
of seed per acre, using a pinch, or 10 to 12 seed, per hill. If hills are
spaced 6 feet apart, the amount of seed required per acre will be about
2y2 pounds. About 1 pound of seed per acre will be needed for hills
spaced 18 feet apart.

METHOD OF SEEDING

Where seed is scarce or unavailable tropical kudzu can be propa-
gated by 2-foot stem cuttings planted in 2-inch furrows on prepared
ground (7, pp. 270-271). The cuttings should be spaced about 3 feet
apart. In rainy weather the cuttings root readily and a 6- to 9-inch
cover can be obtained in 3 to 4 months.

Seeding is used more than cuttings in Puerto Rico because the plants
seed readily and heavily in many sections of the island. On the north
side of the island where rainfall is relatively uniform, the seed can be
sown on slightly sunken hills and covered with a thin film of soil to
prevent them from being washed away. On the south side of the
island in regions where conditions are relatively dry, it is preferable to
cover the seed with about one-eighth inch of soil by pulling a small
brush bundle over the bed. Germination is usually better and quicker
if the soil is then tamped lightly with the foot or with a mattock. If
there is danger of blackbirds and pigeons eating the seed, it is best to
cover the seed with soil and perhaps a brush bundle.

FERTILIZERS

At planting time, the soil, if low in fertility, should be fertilized
only in those areas where the seeds are to be planted. If the fertilizer
is spread uniformly over the entire field, it not only wastes material
but creates a greater weeding problem. A complete fertilizer such as
10-10-5 at the rate of about 400 to 600 pounds per acre, or about %
pound per hill (hills 3 feet apart), is sufficient. For convenience in
application, a tin can may be calibrated by placing % pound of ferti-
lizer in the can and cutting the upper portion of the can off above the
fertilizer level. The fertilizer should be thoroughly mixed with the
upper 3 to 4 inches of soil (fig. 10) ; otherwise, the seedlings may be
burned by the concentrated salts. Manure, if available, at the rate of
1 to 3 tons per acre mixed with the soil only in the areas of seeding
is also effective in getting the seedlings off to a good start.

After the tropical kudzu has become established, the amount of
fertilizer and frequency of application will depend upon the initial
soil fertility and the amount of grazing. If the soil is reasonably
fertile, fertilizer applications may be spaced at 2- or 3-year intervals
or eliminated entirely. However, in case of the upland soils which
are being grazed three or more times a year, it may be necessary to

22

CIRCULAR NO. 27, FEDERAL EXPERIMENT STATION

apply superphosphate and potash once every 1 or 2 years. Super-
phosphate can be applied at the rate of 600 pounds per acre and muri-
ate of potash at 150 pounds per acre. Nitrogen fertilizer is not needed
after the planting has become established, since tropical kudzu is a
legume and this element is furnished to the plant by the nitrogen-
synthesizing bacteria in the root nodules.

In the Tropics, where there is an abundance of rainfall and where
rapid leaching of nutrients is a problem, more frequent applications
of fertilizer are necessary than in temperate regions. In the con-
tinental United States, for example, Bailey (4) suggests an applica-
tion of 600 pounds of superphosphate and, where necessary, 100
pounds of muriate of potash per acre every third year in order to
maintain production of kudzu on marginal and submarginal land.

Figure 15. — A fertilizer experiment on excavated Catalina clay soil (A) revealed
that lime alone (poor growth this side of hat) and muriate of potash (plot
just beyond hat) had little elfect on growth of kudzu seedlings, whereas com-
plete fertilizer (background and immediate foreground) gave the seedlings a
good start. Finely ground superphosphate was used on plot in (B) at the
right. A complete fertilizer is recommended for seedlings, and if the soil pH
is below 5.0, lime also should be applied.

About double this amount is recommended under tropical conditions,
where, it should be pointed out, the plant is growing 12 months of the
year, as compared with 7 to 9 months in the States. It has been em-
phasized by Blaser and associates (6) that applications of fertilizers
to pastures definitely increase the nutritive value of the forage.

If there is some doubt as to the need of phosphorus or potash, test
applications of these elements separately and combined can be made
by the farmer on small areas 50 feet square. If a definite response in
growth occurs after 4 to 6 months, it would be well to fertilize the
entire area. There is some indication on Catalina soil, for example,
that potash is needed only in small quantities, if at all, as shown in
figure 15, A, whereas finely ground superphosphate (fig. 15, B) gave

TROPICAL KUDZU IN PUERTO RICO

23

definitely beneficial results, which is in agreement with Roberts
(14, V> ? wno reports that Catalina soils are low in phosphorus.
This is also in agreement with the results of Richardson (12) in Mis-
sissippi, where Pueravia thunbergiana gave the best response to
applications of superphosphate.

The best time to fertilize established plantings of kudzu is immedi-
ately after the pasture has been cut or grazed to the point where the
majority of the foliage has been removed. If the fertilizer is applied
directly on the dense foliage of ungrazed tropical kudzu, it may cause
severe burning of the foliage. If fertilization is necessary under such
conditions, it can be spread by hand under the foliage in 2- to 3-foot
strips spaced about 6 feet apart. Tropical kudzu becomes so inter-
twined over the entire area that all plants eventually get the benefit of
such strip fertilization. It is unwise to fertilize during the dry season.

In conclusion, it should be stated that soils in general in Puerto Rico
vary considerably in fertilizer requirements and in order to play safe
in securing a quick, thrifty stand of tropical kudzu. it would be well to
use a complete fertilizer at planting or about a month later. Later
applications of phosphorus, lime, or potash can be determined by
preliminary trials on a small scale.

PASTURING

During the grazing experiments at Mayaguez, the statioirs Guern-
sey cows developed a liking for tropical kudzu, especially during the
dry season when plantings of elephant grass, guinea grass, Guatemala
grass, and Para grass and other common pasture crops did not produce
sufficient forage. When the herd was first introduced to tropical
kudzu in January 1945, several cows began eating immediately, while
others ate a leaf here and there but preferred to graze on grass outside
the kudzu plot. Within a day or two, however, all cows fed equally
well.

It is estimated that about 1 acre of tropical kudzu will feed one
cow grazing continuously during the dry season and two cows during
the rainy season. Where pastures are grazed alternately by several
cows, at least a 6-week interval should intervene between each grazing
period. This gives ample time for the droppings to dissolve and a
good cover of foliage to develop. In general, tropical kudzu should
be grazed only once during the dry season, and it is recommended that
the cows not be placed upon the kudzu until other pastures and forage
have become definitely deficient, which is usually about the middle
of the dry season. This reserves the green fresh kudzu for periods
when pastures are beginning to show burning. Care should be taken
that the kudzu is not grazed completely to the ground. Such grazing
may cause a weak come-back. After some observations, the farmer
can judge for himself the best grazing procedure with respect to his
individual soil, climatic, and herd conditions.

Tropical kudzu has produced from 12 to 20 tons of green forage
per acre per year at Mayaguez, depending upon soil fertility and wea-
ther conditions. An acre of this legume produces from two to four
times as much forage of better quality as compared with the native
volunteer pasture grasses. It has been grazed with success by work
oxen and goats as well as milk cows, and probably is equally adapted

24 CIRCULAR NO. 2 7, FEDERAL EXPERIMENT STATION

to other livestock such as poultry. When alfalfa became scarce in
Mississippi during the war, Polk and Gieger (11) demonstrated that
a 9-percent kudzu meal can be readily substituted for the commonly
used alfalfa meal in chick rations.

Tropical kuzdu is relatively high in protein as compared with most
forage crops, such as elephant grass, guinea grass, Para grass, and
similar grasses commonly fed to cows in Puerto Rico. Protein for a
given weight of dry kudzu is from two to four times the amount found
in the above grasses, as shown in table 2.

Table 2. — Chemical analyses of tropical kudzu as compared with
common pasture crops in Puerto Rico

Constituent

Tropical

Entire
above-
ground
portion of
plants 2

kudzu i

Leaves
and young
stems only

(April
1945)

Guinea
grass
(Panicum
maximum

Jacq.)3

Elephant
grass (Pen-

nisetum
purpureum
Schumach)4

Para grass
(Panicum
purpuras-

cent
Kaddi.p

Molasses

grass
(Melinis
minudflora
Beauv.)3

Trailing
indigo
(Indigofera
endeca-
phylla
Jacq.)5

Ash 6

5. 65

8. 00

8. 12

10. 40

7. 78

5. 99

9. 83

Proteins

15. 43

22. 78

4. 26

7. 50

7. 50

6. 38

19. 56

Ether extract - _

3. 54

4. 84

2. 57

3. 24

2. 37

3. 31

4. 33

Fiber

35. 52

28. 62

41. 74

32. 88

33. 52

37. 62

27. 24

Nitrogen-free

extract

39. 86

35. 76

43. 31

45. 98

48. 83

46. 70

39. 04

1 Analysis by Victor L. Quinones, assistant chemist, Insular Agricultural
Experiment Station, Rio Piedras, P. R. Right column shows analyses based
upon portions of vines largely utilized by grazing cows.

2 Average of samples taken in January, May, and September; there was no
marked effect of season on chemical analysis of tropical kudzu.

3 Analyses taken from Axtmayer, Rivera Hernandez, and Cook (3) . (See
table 3.)

4 Axtmayer, Asenjo, and Cook (£). (See p. 119.)

5 Analyzed by D. H. Cook, School of Tropical Medicine of the University of
Puerto Rico, San Juan, P. R.

6 The average percentage of moisture in green forage was about 75 percent ;
all figures are expressed on dry basis.

It is evident that a combination of tropical kudzu with a grass such
as Para grass is highly desirable in order to increase the protein con-
tent of the forage and reduce the need for supplemental commercial
feeds which are relatively expensive. Trailing indigo, likewise, is
high in protein, but this crop is somewhat more difficult to establish,
produces about half the forage, and does not withstand drought as
well as tropical kudzu (see fig. 16) .

HARVEST OF SEED

Because of the scarcity of seed it may be impossible for farmers to
secure more than one-fourth of a pound of seed at the outset.17 This
amount will plant about one-eighth of an acre for trial and seed pro-
duction. The seed can be harvested from this initial plot and stored

17 Contact your local county agricultural agent or soil conservationist regarding
source of seed.

TROPICAL KXDZU IN PUERTO RICO

25

Figure 16. — Photographs show the amount of growth obtained with molasses
grass (A), trailing indigo (B), and tropical kudzu (C) 6 months after plant-
ing. Two months later during a severe drought, the tropical kudzu was defi-
nitely superior to the other two crops in furnishing forage for dairy cows. The
trailing indigo, in fact, showed considerable distress.

26 CIRCULAR NO. 2 7, FEDERAL EXPERIMENT STATION

in jars under ordinary room temperature and humidity conditions
until planting time.

Tropical kuclzu flowers and seeds heavily at Mayaguez beginning in
November and extending to the following March. It apparently
fruits more heavily in regions where there is a definite dry period
than in areas such as those in Malaya where rainfall is heavy and well
distributed pp. 238-239) .18 Seed and forage production can be
increased per unit of ground by erecting tripods at 15- to 25-foot
intervals (fig. 17), or by using living posts such as dwarf bucare
(Erythrina hertereana Urban). It appears that mechanical harvest-
ing may not be desirable because of the fact that the seed ripens over
a period of 3 or 4 months. Insofar as is known, the seed is harvested
entirely by hand (fig. 18) , and it requires about 1 hour for one man to
harvest a pound (36,000 seed per pound). One acre has produced

Figure 17. — Tropical kudzu seeds more heavily if staked. Note poor cover of
Pueraria thunder giana under tropical conditions in plot to left.

about 150 pounds of seed. It is necessary to go over the field sys-
tematically once or twice a week, picking only the black ripe pods.
Five gallons of pods will yield about 2.7 pounds of seed. The har-
vested pods are laid in the sun, where they soon dry and break open.

See footnote 4. p. 3.

TROPICAL KUDZU IN PUERTO RICO

27

The pods and seed are then placed in a sack or basket and beaten gently
against the wall to knock the seed to the bottom of the container.

INSECTS AND DISEASES

During 5 years of experimentation with tropical kudzu at many
different locations over the island, no serious diseases or insects have
developed. Probably because of the pubescense of the foliage, little
or no trouble has been encountered with the velvetbean caterpillar
(Anticarsia gemmatilis (Hbn.) ). which has been one of the limiting
factors with the smooth-leaved Pueraria thunbergiana. From October
to January, there is a leaf tier (Hedylepta indicata (F.) ), which eats

Figuee 18. — Seed is being harvested by hand in this heavily fruiting field of tro-p-
local kudzu ; fruiting stalks are so thick that many of the leaves are obscured.
One man can harvest about 1 pound of seed per hour.

holes in the leaves and rolls the margins, but this insect does not appear
to be important.

The only disease encountered was an unidentified wilt which ap-
peared in spotted areas over a 2-acre planting of tropical kudzu near
Maricao on Nipe cla}'. The stems became soft brown and rotted as
shown in figure 19, which resulted in patches of yellow and dead leaves.
Runners from neighboring plants, however, were gradually covering
these "blighted" areas. There is some indication that this may be clue
to low phosphorus in the soil.

Both the insect and disease noted above were considered to be of
minor importance. The literature reviewed contains no reference to
additional insect or disease troubles.

28 CIRCULAR XO. 2 7, FEDERAL EXPERIMENT STATION

Figure 19. — An unidentified wilt in scattered patches near Maricao, P. R., was
the only disease noted on tropical kudzu. The same disease was found attack-
ing neighboring plots of trailing indigo, but the amount of injury in both
instances was of minor importance. Runners turned from soft brown to black,
and the leaves became yellow and died.

LITERATURE CITED

(1) ASHPLANT, H.

1940. THE REPLANTING OF OLD RUBBER AREAS, AND ROOT DISEASE. India

Rubber Jour. 99: 342-344 (No. 14, pp. 8-10), illus.

(2) Axtmayer, J. H., Asenjo, C. F., and Cook, D. H.

1938. the nutritive values of some forage crops of Puerto rico. Puerto
Rico Univ. Jour. Agr. 22 : 119-121.

(3) Rivera Hernandez, G., and Cook, D. H.

1940. chemical analyses of grasses. Puerto Rico Univ. Jour. Agr. 24 :
32-34.

TROPICAL KUDZU IN PUERTO RICO

29

(4) BAILEY, R. Y.

1943. kudzu conserves southern soils. Better Crops With Plant Food

27 (9) : 21-30, 48-49, illus.

(5) Bentham, G.

1867. NOTES ON PUERARIA, DC, CORRECTLY REFERRED BY THE AUTHOR TO

phaseoleae. Linnean Soc. London, Jour. Bot. 9 : 121-125.

(6) Blaser, R. E., Stokes, W. E., Warner, J. D., and others.

1945. pastures for Florida. Fla. Agr. Expt. Sta. Bui. 409, [78] pp., illus.

(7) Bunting, B., and Milsum, J. N.

1928. cover crops and green manures. Malayan Agr. Jour. 16 : 256-280,
illus.

(8) Hosaka, E. Y., and Ripperton, J. C.

1944. legumes of the Hawaiian ranges. Hawaii Agr. Expt. Sta. Bui.

93, 80 pp., illus.

(9) International Institute of Agriculture.

1936. use of leguminous plants in tropical countries as green manure,
as cover and as shade. 262 pp., illus. Rome.

(10) KlNMAN, C. F.

1916. cover crops for porto rico. Porto Rico (Mayaguez) Agr. Expt. Sta.
Bui. 19, 32 pp. illus.

(11) Polk, H. D., and Gieger, M.

1945. kudzu in the ration of growing chicks. Miss. Agr. Expt. Sta.

Bui. 414, 14 pp., illus.

(12) Richardson, E. C.

1945. THE EFFECT OF FERTILIZER ON STAND AND YIELD OF KUDZU ON DEPLETED

soils. Jour. Airier. Soe. Agron. 37 (9) : 763-770, illus.

(13) Ripperton, J. C.

1945. case for kudzu? Hawaii Farm and Home 8 (7) : 2, illus.

(14) Roberts, R. C, Thorp, J., Smith, L. R., and others.

1942. soil survey of Puerto rico. U. S. Bur. Plant Indus., Soil Surv. Ser.
1936, No. 8, 503 pp., illus.

(15) SCHOFIELD, J. L.

1945. A COMPARISON OF SOIL NITRATE NITROGEN VALUES UNDER BARE FALLOW
AND AFTER PLOUGHING IN VARIOUS PERENNIAL TROPICAL LEGUMES AND

cowpeas. Queensland Jour. Agr. Sci. 2 : 170-189, illus.
ADDITIONAL REFERENCES

(1) Baalen, J. van, and Heubel, G. A.

1938. DE MEEST DOELMATIGE GRONDBEDEKKING IN VOLWASSEN RUBBERTUINEN.

Bergcultures 12 : 585-597.

(2) Balley, R. Y.

1944. KUDZU FOR EROSION CONTROL IN THE SOUTHEAST. U. S. Dept. Agr,

Farmers' Bui. 1840, 30 pp., illus.

(3) Basu, B. C.

1902. THE CULTIVATION OF PULSE CROPS IN THE ASSAM VALLEY. Assam Agr.

Dept. Bui. 9 : 15 pp. ( See pp. 14-15. )

(4) ■

1903. THE CULTIVATION OF PULSE CROPS IN THE ASSAM VALLEY. Agl*. Ledger

10: [125J-137. ( See pp. 136-137. )

(5) Driessen, F. C.

1941. DE BETEEKENIS VAN DEI GROENBEMESTING VOOR DE OVERJARIGE CULTURES.

Bergcultures 15 : 458-469.

(6) Federated Malay States Department Agriculture.

1934. cover crops. Fed. Malay States, Dept. Agr., Agr. Ser. Leaflet 6,
4 pp.

(7) Holland, T. H.

1931. ALTERNATIVE GREEN MANURE PLANTS. Trop. Agl*. [Ceylon] 76.'

135-136.

(8) Keuchenius, A. A. M. N.

1924. BOTANISCHE KENMERKEN EN CULTUURWAARDE ALS GROENBEMESTER
VAN EEN 60-TAL NIEUWE SOORTEN VAN LEGU MI N O SEN . [Dutch East

Indies] Proefsta. v. Thee Meded. No. 90, 44 pp., illus. (See
p. 38.)

(9) Van Helten, W. M.

1924. PRACTTSCHE ERVARINGEN MET VEESCHILLENDE SOORTEX GROENBE-

mesters. [Dutch East Indies] Alg. Proefsta. v. Landb. Meded.
No. 16, 72 pp., illus. ( See p. 51. )

RECOMMENDED PRACTICES FOR TROPICAL KUDZU

1. Tropical kuclzu is a vigorous, deep-rooted, twining legume,

which is relatively resistant to drought. In Puerto Rico
it is recommended primarily for lowland and upland
pasture areas, for controlling erosion, and for ground
cover in economic tree plantations. It appears to grow
best in regions having not less than 50 inches of rainfall
annually.

2. The nutritive value of a forage grass such as Para grass or

molasses grass can be increased by interplanting with
tropical kuclzu, which is relatively high in protein.

3. The use of tropical kudzu in dairy and beef cattle rations

will reduce the need for expensive imported concentrates.

4. Tropical kudzu can be established from seed and with reg-

ular rains will cover the ground within 6 months after
planting ; it is perennial and grows 12 months of the year.

5. It grows somewhat better on the medium to heavy clays, but

good ground cover has been obtained on sandy loams.

6. Best time for planting seed in Puerto Rico is at the begin-

ning of the rainy season which is between April and May
in most regions ; seed are planted in rows or hills 3 to 20
feet apart, depending upon availability of seed and labor,
and the rapidity with which a ground cover is desired.

7. Seed should be scarified for better germination, and inocu-

lated with a special nodule-forming bacteria for kudzu.

8. Seedlings grow slowly at first, but this can be speeded up by

preparing a fine seedbed 6 to 10 inches deep and fertilizing
with manure and or a complete fertilizer.

9. One or two weedings are necessary to eliminate weed com-

petition with the young seedlings.

10. Since tropical kudzu is a legume, nitrogen applications are

not necessary once the crop is established. Phosphorus
and potassium may be needed at 1- or 2-year intervals,
depending upon the amount of grazing and the fertility of
the soil.

11. Tropical kudzu under favorable soil and climatic conditions

may produce between 12 to 20 tons of green forage per
acre per year and 150 pounds or more of hand-harvested
seed.

U. S. GOVERNMENT PRINTING OFFICE: 1947

For sale by the Superintendent of Documents, U. S. Government Printing Office
Washington 25, D. C. - Price 10 cents